The present invention relates to a sliding gate valve for a bottom-pour teeming ladle comprising a housing containing a slide frame which mounts a slide plate, the latter being urged against a fixed top plate by springs mounted within the frame. The housing is pivotally attached to the bottom of the ladle by a hinge on one side and a releasable latch on the other side. Compression means are provided on both sides of the housing parallel to the direction of movement of the slide frame by means of which, in cooperation with the aforementioned springs, the housing is urged toward the ladle bottom. A sliding gate valve of the involved type is shown and described in U.S. Pat. Application Ser. No. 377,385, filed July 9, 1973, by E. P. Shapland and J. T. Shapland now abandoned.
Sliding gate valves of the described type employ compression means in the form of toggle levers that pivot about axes parallel to the direction of movement of the slide frame and which, through such pivoting motion, create the preload force upon the springs. Pivoting of the toggle levers is accomplished manually by two actuating rods that engage the levers.
Manual actuation of the toggle levers has several disadvantages. Because the preload forces are generally very great, the actuating rods frequently cannot be simultaneously operated by a single workman, even though the rods may be of extended length. This leads to a situation where the actuating rods must be operated in sequence thus creating the possibility of distorting the housing. Even where two workmen are utilized, each operating the respective rods, a precisely uniform operation of the toggle levers cannot be guaranteed. It is apparent that improper operation of the toggle levers can cause misalignment of the housing and produce severe upsets in the pouring operation.
It is therefore the aim of the present invention to provide an improved sliding gate valve of the described type that permits simultaneous operation of both toggle lever actuating rods and without the use of the manual efforts of workmen whereby the above disadvantages are avoided.